Instantaneous switch

ABSTRACT

The invention relates to switches used in the automatic drive control of hoisting and conveying plant, machine-tools and other industrial equipment and, more specifically, to instantaneous switches used as limit switches. The instantaneous switch contains fixed contacts, fastened to the base, movable contacts, an operating element, two levers and two spiral springs. The ends of the levers are connected to the ends of the springs and bear against the fixed limit stops made fast to the base. The free ends of the levers are hinged and carry movable contacts. The operating element is jacked up by an opposing spring placed in a sleeve fastened to the base. The movable contacts of the switch, built into the base, are protected by a cover fastened to the base with pipes.

United States Patent [191 Poltorak et a1.

[ INSTANTANEOUS SWITCH [76] Inventors: Alexandr Pavlovich Poltorak,ulitsa Schorsa, 25, kv. 1; Svyatoslav Semenovich Nedosekov, bulvarShevchenko, 71, kv. 15, both of Donetsk; Jury Fedorovich Sameljuk,ulitsa Njutona, 139-b, kv. 6, Kharkov; Oleg Mikhailovich Vorontsov,ulitsa Shakhtera, l4, kv. 5, Makeevka; Nikolai Nikitovich Sashkin,Stavropolsky krai, Lenina, 48, kv. 6, Selenokumsk, all of U.S.S.R.

[22] Filed: Nov. 12, 1971 [21] Appl. No.: 198,308

[52] 11.8. C1. 200/76, 200/67 A, 200/67 B [51] Int. Cl. ..l-l01h 15/18[58] Field of Search 200/76, 67 A, 67 B,

[56] References Cited UNITED STATES PATENTS 2,472,333 6/1949 Kohl 200/762.791.656 5/1957 Dehn et a1. 200/76 3,017,471 1/1962 Karch 200/762,412,119 12/1946 Bentley 200/76 2,629,791 2/1953 Tourneau 200/76 Oct.9, 1973 FOREIGN PATENTS OR APPLICATIONS 1,342,806 10/1963 France 200/76730,991 1/1955 Great Britain 29,953 8/1964 Germany 200/76 PrimaryExaminer-David Smith, Jr. AttorneyEric l-l. Waters et al.

[57] ABSTRACT The invention relates to switches used in the automaticdrive control of hoisting and conveying plant, machine-tools and otherindustrial equipment and, more specifically, to instantaneous switchesused as limit switches.

The operating element is jacked up by an opposing spring placed in asleeve fastened to the base.

The movable contacts of the switch, built into the base, are protectedby a cover fastened to the base with pipes.

4 Claims, 13 Drawing Figures SHEET 10F 6 PATENTEU BET 19 3 PATENTED BET91973 SHEET 6 OF 6 HEM INSTANTANEOUS SWITCH The present inventionrelates to switches used in the automatic drive control of hoisting andconveying plant, machine-tools and other industrial equipment and, morespecifically, to instantaneous switches used as limit switches.

in limit switches the contacts are thrown over when an adjustable stop(cam) of the machine actuates the operating mechanism of the switch.

when the adjustable stop of the machine moves slowly, and the speed atwhich the contacts are thrown over depends on that of the adjustablestop, as is the case with direct-action switches, the time intervalbetween the instant the contacts just touch under electrical load andthe instant when they build up sufficient contact pressure is relativelylong.

A prolonged dwell in the closed position under electrical load coupledwith insufficient pressure and slow contact throw-over may cause serioustroubles such as: fusing, burning and even welding of the contacts.

To prevent these troubles in the contacts due to the slow movement ofthe adjustable stop, limit switches incorporate a means of speeding upthe throw-over of the movable contacts.

Known in the prior art are semi-instantaneous switches with switch-onand throw-over times practically independent of the position and speedof the operating element. However, as the operating element shifts,contact pressure in these switches changes from the rated to the minimumvalue and even decreases to zero near the throw-over of the contacts.

The semi-instantaneous switches have a means for throwing over themovable contacts, actuated by the operating element and containing twosprings symmetrically arranged on both sides of the axis of theoperating element or two rigid levers interconnected by a spring.

Since contact pressure is semi-instantaneous switches varies as fast asthe adjustable stop of the machine moves, such switches can operatetrouble-free in machines in which the adjustable stop has a speed of atleast 0.3 m/min.

If the controlling adjustable stop of a machine moves at a speed lowerthan 0.3 m/min., the limit switches use instantaneous switches withcontacts whose switch-on and throw-over times and pressure arepractically independent of the position of the operating element duringswitch-off, switch-on or throw-over and, consequently, of the speed.

Known in the prior art are instantaneous switches whose means forthrowing over the movable contacts into extreme positions consists oftwo interconnected means of the prior art semi-instantaneous switches,namely: a first means made up of two springs interconnected by a lever,and a second means made up of two additional springs.

In these instantaneous switches, the operating element actuates thefirst movable-contact throw-over means, and the movable contacts areconnected with the second means. The joints between the first and secondmeans bear against limit stops.

In the prior-art instantaneous switches, the movablecontact throw-overmeans has two spring systems containing at least three springs.Mechanically, the priorart instantaneous switches consist of a largenumber of parts, which adds to their overall dimensions, weight and,consequently, the overall dimensions and weight of the limit switchesinto which they are built.

When the prior-art instantaneous switches operate under conditions ofheavy impacts and vibration, the effect of external forces on their basecauses a countermovement of the masses of the operating element and thelever interconnecting the two springs and, consequently, of the leverand movable contacts. In this process, all the springs of themovable-contact throw-over means are in a position ensuring maximumcontact pressure. Because of this, the prior-art instantaneous switcheshave low stability against vibration and impacts, just as the prior-artsemi-instantaneous switches.

Also known in the prior art is an instantaneous switch disclosed inJapanese Pat. No. 59A5l 39-16723 containing fixed contacts fastened tothe base and mating movable contacts, a means for throwing over themovable contacts compirsing an operating element, a spiral spring, twolevers and two leaf springs, symmetrically arranged on both sides of theaxis of the operating element. At one end, the levers are connected tothe ends of the leaf springs and the ends of the spiral spring and bearagainst the limit stops secured to the base, while the other ends of thelevers are hinged to the fixed base support. The operating elementactuates the middle part of the spiral spring. The movable contacts areconnected to the free ends of the leaf springs.

Thus, the means for throwing over the movable contacts of the prior-artinstantaneous switch has thre springs and two levers.

Many attempts have been made to develop a simple, lightweight andsmall-size instantaneous switch, but none has been fully successful inrealizing a commercial instantaneous switch.

It is an object of the present invention to provide an instantaneousswitch which is simple in design, smaller in size, lighter in weight andhas fewer parts than the prior-art instantaneous switch, while itscontact switchon or throw-over time and contact pressure are practicallyindependent of the position and, consequently, the speed of theoperating element.

Another object of the present invention is to provide instantaneousswitches with high mechanical and electrical wear resistance.

Still another object of the invention is to provide an instantaneousswitch possessing high impact and vibration resistance and stabilityagainst linear accelerations.

With these objects in view, the invention resides in that aninstantaneous switch comprising fixed contacts, secured to the base,mating movable contacts, a movable-contact throw-over means made up ofat least two interconnected assemblies arranged symmetrically about theaxis of the operating element and consisting each of at least one springelement and a lever, so that at one end the levers are connected to theends of the spring elements bearing against limit stops made fast to thebase, while the operating element actuates the said means at the jointbetween the two assemblies, according to the invention, the free andhinged ends of the assemblies are spaced closer than the limit stops andcarry the movable contacts.

Also with these objects in view, in the instantaneous switch one of theassemblies of the movable-contact throw-over means is integrated withanother such unit.

With the same objects in view, in the instantaneous switch themovable-contact throw-over means is made in the form of a single elasticplate the outer parts of which are bent lengthwise and the inner partshave the shape of two tongues.

The invention will be more fully understood from the following detailedinscription when read in connection with the accompanying drawingswherein specific narrow terms are used for making the description morelucid, but the invention is not confined to the accepted narrowterminology, and it should be borne in mind that each term covers allequivalent elements operating in the same wayand used for achievingobjects analogous to those of the present invention.

It should also be borne in mind that other objects and advantages of thepresent invention, besides those indicated above, will be revealed belowin the description when read in connection with the following drawingswherein:

FIGJ shows a front view, with the cover partially removed, of apreferred embodiment of an instantaneous switch;

FIG.2 shows details of the switch of FIGJ;

FIG.3 shows a section taken on line IIIlII of FIGJ;

FIGA shows a front view, with the base wall partially removed, of asecond embodiment of the instantaneous switch;

FIG.5 shows a detail of the switch of FIGA;

FIG.6 shows a front view, with the base wall partially removed, of athird embodiment of the instantaneous switch;

FIG.7 shows details of the switch of FIG.6;

FIG.8 shows a front view, with the base wall partially removed, of afourth embodiment of the instantaneous switch;

FIG.9 shows details of the switch of FIGS;

FIGJO shows a front view, with the cover partially removed, of a fifthembodiment of the instantaneous switch;

FIGJI shows details of the switch of FIGJI);

FIG.12 shows a front view, with the base wall partially removed, of asixth embodiment of the instantaneous switch;

FIG.I3 shows details of the switch of H612 According to the invention,the instantaneous switch contains fixed contacts 1 and 2 (FIGS. 1 and2), fastened to a base 3, made of an insulating material, mating movablecontacts 4, an operating or actuating element 5 and a movable-contactthrow-over means made up of two assemblies arranged symmetrically aboutthe axis of the operating element 5, each assembly consisting of a lever6 and a spring element in the shape of a spiral spring 7. Ends 8 of thelevers 6 are connected to ends 9 of the springs 7 and bear against limitstops 10, made fast to the base 3 and in the shape of metal clamps. Theoperating element 5 actuates the movable-contact throw-over means at thejoint of the two assemblies, namely, at the contact points of the otherends 11 of the springs 7 (FIG.3).

Free ends 12 of the levers 6, opposite to ends 8 bearing against thelimit stops l0, and to ends 11 of the springs 7, i.e., to the partsactuated by the operating element 5, are hinged together and carry themovable contacts 4. The free ends 12 are closer to the said axis of theoperating element 5 than the limit stops 10.

The operating element 5 is jacked up by an opposing,

spring 13 placed in a sleeve 14 fastened to the base 3. The fixedcontacts 1 and 2 are connected to clamps 15 to which control circuitwires are connected whenever necessary. The movable parts of the switch,built into the base 3, are protected by a cover 16 fastened to the base3 with pipes 17.

When an external force influences the operating element 5, the ends 11of the springs 7 move downwards, and when they cross the lines drawnthrough the ends 8 and 12 of the levers 6, the movable contacts 4 arethrown over.

When the external force ceases to influence the operating element 5, allthe movable parts of the switch are returned to their initial positionby the spring 13.

A second, explosion-proof, embodiment of the instantaneous switchcontains the fixed contacts 18 (FIGS. 4 and 5), fastened to a base 19,made of insulation material, mating movable contacts 20, connected tocontact bridges 21, an operating element 22 and a movable-contactthrow-over means made up of two as semblies arranged symmetrically aboutthe axis of the operating element 22, each assembly consisting of alever 23 and a spring element made in the shape of a leaf spring 24.Ends 25 of the levers 23 are connected to ends 26 of the springs 24 andbear against the limit stops l0 fastened to the base 19.

The operating element 22 consists of a clamp 27 with catches 28, aroller 29 and a hood 30.

Fastened to the levers 23 are brackets 31 against which the ends 26 ofthe springs 24 bear.

The contact bridges 21 are secured by the springs 32 to a contact holder33 made of an insulating material.

The operating element 22 actuates the movablecontact throw-over means atthe joints between the two assemblies and, namely, in the points ofcontact between the catches 28 and other ends 34 of the levers 23.

The free ends 35 of the springs 24, opposite to the ends 26 bearingagainst the limit stops 10, and to ends 34 of the levers 23, i.e., tothe parts actuated by the operating element 22, are hinged and carry themovable contacts 20. The free ends 35 are closer to the said axis of theoperating element 22 than the limit stops 10.

The fixed contacts 18 are connected to the clamps 15 to which controlcircuit wires are connected whenever necessary.

The movable parts of the switch, built into the base 19, are protectedby a cover 36 fastened to the base 19 with screws 37.

When an external force influences the operating element 22, ends 34 ofthe levers 23 move downwards, and when they cross the lines drawnthrough the ends 26 and 35 of the springs 24, the movable contacts 20are thrown over.

When the external force ceases to influence the operating element 22,all the movable parts of the switch are returned to their initialposition by, the spring 38.

The third embodiment of the instantaneous switch contains fixed contacts18 (FIGS. 6 and 7), fastened to a base 39 made of an insulatingmaterial, mating movable contacts 20, connected to the contact bridges21, operating element 40, in the shape of a hood, and movable-contactthrow-over means made up of two assemblies arranged symmetrically aboutthe axis of the operating element 40, each assembly consisting of alever 41 and a spring element made in the shape of a link 42 connectedto another such link by a spring 43. Ends 44 of the levers 41 areconnected to ends 45 of the links 42 and bear against the limit stops1!) fastened to the base.

The contact bridges 21 are made fast to the contactholder 46, made of aninsulating material, by means of the springs 32. The operating element40 actuates the movable-contact throw-over means at the joints betweenthe assemblies, namely, the spring 43.

The free ends 47 of the levers 41, opposite to the ends 44 bearingagainst the limit stops 10, are hinged and carry the movable contacts20. The fixed contacts 18 are connected to the clamps to which controlcircuit wires are connected whenever necessary.

The free ends 47 of the levers 41 are closer to the said axis of theoperating element 40 than the limit stops 10.

The movable parts of the switch, built into the base 39, are protectedby the cover 48 secured to the base 39 by the pipes 49.

When an external force influences the operating element 40, ends 50 ofthe links 42 move downwards, and when they cross the lines drawn throughthe ends 44 and 47 of the levers 41, the movable contacts are thrownover.

When the external force ceases to influence the operating element 40,all the movable parts of the switch are returned to their initialposition by the opposing spring 51 which bears against a plate 52 madefast to the base 39.

The fourth embodiment of the instantaneous switch contains fixedcontacts 18 (H688 and 9), fastened to the base 53 made of an insulatingmaterial, mating movable contacts 20, secured to contact bridges 21, theoperating element 54 and movable-contact throwover means made up of twoassemblies arranged symmetrically about the axis of the operatingelement 54, each assembly consisting of the levers 55 made integral of athin elastic material in the shape of a frame 56 and a spring element inthe shape of a link 57 connected to another such link by a spring 58.The ends 59 of the levers 55 are connected to the ends 60 of the links57 and bear against the limit stops l0 fastened to the base. The contactbridges 21 are fastened by the springs 32 to the contact holder 61 madeof an insulating material.

The operating element 54 consists of a clamp 62 with catches 63, aroller 29 and a hood 30.

By its catches 63, the operating element 54 actuates the movable-contactthrow-over means at the joints between the two assemblies, namely, themiddle parts of the frame 56.

The free ends 64 of the links 57, opposite to the ends 60 that bearagainst the limit stops 10, are hinged by means of contact holders 65placed in an aperture 66 of the contact holder 61 and carry the movablecontacts 20. The free ends 64 of the links 57 are closer to the saidaxis of the operating element 54 than the limit stops 10.

The movable parts of the switch built into the base 53 are protected bythe cover 67 fastened to the base 53 by the screws 37.

When an external force influences the operating element 54, the catches63 bend in the middle part of the frame 56 and, when the levers 55 arealigned with the links 57, the movable contacts 20 are thrown over.

When the external force ceases to influence the operating element 54,the movable parts of the switch are returned to their initial positionby the spring 38.

The fifth embodiment of the instantaneous switch contains the fixedcontacts 18 (FIGS. 10 and 11), fastened to the base 68 made of aninsulating material, the

mating movable contacts 20 fastened to the contact bridges 21, theoperating element 69 and the movablecontact throw-over means made up oftwo assemblies arranged symmetrically about the axis of the operatingelement 69, each assembly consisting of the lever 70 and a springelement in the shape of a leaf spring 24.

The levers 70 are of wave shape, aligned and turned 180 relative to eachother about an axis perpendicular to the axis of the operating element69. Ends 71 of the levers 70 are connected to the ends 26 of the springs24 and bear against the limit stops l0 fastened to the base 68. Theoperating element 69 consists of a hood 72 and a clamp 73.

The contact bridges 21 are fastened by the springs 32 to the contactholder 74 made of an insulating material. Fastened to the levers 70 arethe brackets 31 against which the ends 26 of the spring 24 bear.

Fastened to the contact holder 74 is a clamp 75 with brackets 76. Theoperating element 69 actuates the movable-contact throw-over means atthe joints between the two assemblies, and namely in the points ofcontact between the clamps 73 and other ends 77 of the levers 70.

The free ends 35 of the springs 24, opposite to the ends 26 that bearagainst the limit stops 10 and to the ends 77 of the levers 70, arehinged and bear against the brackets 76. The ends 35 carry the movablecontacts 20.

The free ends 35 of the springs 24 are closer to the said axis of theoperating element 69 than the limit stops 10.

The fixed contacts 18 are linked with the clamps 15 to which controlcircuit wires may be connected, if necessary. The movable parts of theswitch, built into the base 68, are protected by the cover 78 fastenedto the base 68 by the pipes 79.

When an external force influences the operating element 69, the ends 77of the levers 70 move downwards, and when they cross the lines drawnthrough the ends 26 and 35 of the springs 24, the movable contacts 20are thrown over.

When the external force ceases to influence the operating element 69,all the movable parts of the switch are returned to the originalposition by a spring 80. The spring 80 bears against a plate 81 madefast to the base 68.

The sixth embodiment of the instantaneous switch contains fixed contacts82 and 83 (FIGS. 12, 13) fastened to a base 84 made of an insulatingmaterial, mating movable contacts 85, an operating element 86 and amovable-contact throw-over means made as a whole plate 87 the outerparts of which are bent lengthwise, and the inner parts are made in theshape of two tongues 88.

The plate 87 and the tongues 88 are made integral of an elasticmaterial, such as berrylium bronze. Ends 89 of the plate 87 bear againstthe limit stops 10.

The operating element 86 consists of a hood 90 and a clamp 91 withcatches 92.

The operating element 86 actuates the movablecontact throw-over means inpart symmetrical to the limit stops l0, namely, in the points of contactbetween the catches 92 and the medium outer parts 93 of the plate 87.

Free ends 94 of the tongues 88, opposite to the ends 89, are hinged bymeans of a bracket 95 and carry movable contacts 85.

The movable bracket 95 slides along a guide 96 fas-- tened to the base84 by means of plates 97. The free ends 94 of the tongues 88 are closerto the said axis of the operating element 86 than the limit stops 10.

The fixed contacts 82 and 83 are linked with the clamps 15 to whichcontrol circuit wires may be connected, if necessary.

The movable parts of the switch, built into the base 84, are protectedby a cover 98 fastened to the base 84 by pipes 99.

When an external force influences the operating element 86, parts 93 ofthe plate 87 move downwards, and when they cross the lines of the ends94 drawn through the tongues 88, the movable contacts 85 are thrownover.

When the external force ceases to influence the operating element 86,all the movable parts of the switch are returned to the initial positionby a spring 100.

As is seen from the description of the invention and the drawings, thedesired objects are achieved as follows. In the instantaneous switchdislosed herein, the movable-contact throw-over means practically doesnot differ, in the number of its components, from the prior-art meansused in semi-instantaneous switches. Thus, the movable-contactthrow-over means of the instantaneous switch disclosed herein maycomprise at least one spring instead of three in the prior-artinstantaneous switches.

The small number of components of the switch disclosed herein permitssimplification of its design, reduction of its overall size and weightand, consequently, reduction of the size and weight of the limitswitches in which it is built into.

In the switch disclosed herein, the joint connection of the free ends ofthe movable-contact throw-over means, opposite to the ends that bearagainst the limit stops and to the parts influenced by the operatingelement, make it possible to ensure a rather high mechanical wearresistance. 7

The instant an external force begins to influence the base of the switchdescribed herein, the levers or springs of its movable-contactthrow-over means are in positions ensuring considerable contact pressureeven in case of a counter-movement of the masses of the operatingelement and movable contacts. As a result, the switch disclosed hereinhas a relatively high electrical wear resistance and stability againstvibration, impacts and linear accelerations.

The invention described above makes it possible to realize commerciallyand in quantity a switch with the switch-on and throw-over times andcontact pressure practically independent of the position of theoperating element and, consequently, of its speed, that is, aninstantaneous switch whose number of parts, overall dimensions andweight are equal to those of the prior-art semi-instantaneous switchesand identical or slightly superior to the prior-art instantaneousswitches in mechanical and electrical wear resistance and in stabilityagainst vibration, impacts and linear accelerations.

It should be borne in mind that the present description and drawingsrelate only to a few preferred embodiments of the switch disclosedherein. Its modifications may differ as regard the shape, size and thearrangement of individual elements. For instance, the parts describedabove and shown in the drawings may be replaced by their equivalents,the position of individual parts may be changed, certain elements of theinvention may be used independently of others if it is within the scopeand meaning of the invention as set forth in the claims. The switchesmade according to this invention may be also used at button controlposts or as retaining contacts in electromagnetic devices like relays,contactors and electromagnets.

What is claimed is: v

1. An instantaneous switch comprising a base,

fixed contacts secured to said base,

mating movable contacts for selective contact with the fixed contacts,

an actuator means for effecting selective contact of the movablecontacts with the fixed contacts and means for throwing over the movablecontacts to end positions in which they make selective contact with thefixed contacts, said means including at least two units symmetricallylocated with respect to said actuator and operatively coupled therewith,each unit including at least one spring member having opposite ends,

a lever having opposite ends, the levers and the spring members of theunits being symmetrically disposed with respect to the actuator, thelevers and spring members having respective ends remote from theactuator which are coupled together, and

fixed limiters secured to the base, said levers bearing against thelimiters at the ends thereof where the levers are connected to thespring members, the other ends of the spring members and leversconstituting free ends of the units,

some of said free ends being connected to the actuator, the other ofsaid free ends being located at a distance from each other which is lessthan the distance between said limiters and being hinged together andcarrying said movable contacts.

2. An instantaneous switch as claimed in claim 1 wherein the levers andspring members have inner ends closer to the actuator and outer endsfurther away from the actuator, the other of said free ends being theinner ends of the levers, the free ends connected to the actuator beingthe inner ends of the spring members.

3. An instantaneous switch as claimed in claim I wherein:

said units are aligned with one another.

4. An instantaneous switch as claimed in claim 1 wherein each said unitis in the form of a single elastic plate the outer portions of which arebent lengthwise and the inner portions have the shape of two tongues,the other portions being the spring members, the inner portions beingsaid tongues. The movable parts of the switch, built into the base 68,are prtected by thecover 78 fastened to the base 68 by the pipes 79.

1. An instantaneous switch comprising a base, fixed contacts secured tosaid base, mating movable contacts for selective contact with the fixedcontacts, an actuator means for effecting selective contact of themovable contacts with the fixed contacts and means for throwing over themovable contacts to end positions in which they make selective contactwith the fixed contacts, said means including at least two unitssymmetrically located with respect to said actuator and operativelycoupled therewith, each unit including at least one spring member havingopposite ends, a lever having opposite ends, the levers and the springmembers of the units being symmetrically disposed with respect to theactuator, the levers and spring members having respective ends remotefrom the actuator which are coupled together, and fixed limiters securedto the base, said levers bearing against the limiters at the endsthereof where the levers are connected to the spring members, the otherends of the spring members and levers constituting free ends of theunits, some of said free ends being connected to the actuator, the otherof said free ends being located at a distance from each other which isless than the distance between said limiters and being hinged togetherand carrying said movable contacts.
 2. An instantaneous switch asclaimed in claim 1 wherein the levers and spring members have inner endscloser to the actuator and outer ends further away from the actuator,the other of said free ends being the inner ends of the levers, the freeends connected to the actuator being the inner ends of the springmembers.
 3. An instantaneous switch as claimed in claim 1 wherein: saidunits are combined with one another.
 4. An instantaneous switch asclaimed in claim 1 wherein each said unit is in the form of a singleelastic plate the outer portions of which are bent lengthwise and theinner portions have the shape of two tongues, the other portions beingthe spring members, the inner portions being said tongues.